Many industries generate wastewater that is not usable or practical for drinking, agriculture, commercial use, and disposal. The wastewater may contain a high concentration of brine, contaminants, or other chemicals. For example, hydraulic fracturing utilizes pressurized liquid to break up rock formation beneath the ground surface to allow natural gas, petroleum, and brine to flow more freely. The pressurized liquid combines water with chemical additives, where the chemical additives assist in creating pressure to propagate fractures and carry proppant into the fractures. Possible chemical additives can include silica, quartz sand, hydrochloric acid, polyacrylamide, isopropanol, guar gum, hydroxyethyl cellulose, sodium carbonate, potassium carbonate, ammonium persulfate, citric acid, borate salts, N,N-dimethyl formamide, and glutaraldehyde. The pressurized liquid may also pick up naturally occurring substances during hydraulic fracturing, such as sodium chloride, natural gas (e.g., methane, ethane), carbon dioxide, and organic compounds including volatile organic compounds. Wastewater is formed after hydraulic fracturing that contains water along with a variety of chemical additives, volatile organic compounds, salts, and more. Such wastewater cannot be reused for hydraulic fracturing again. More generally, disposal of wastewater in industries such as hydraulic fracturing may be impractical, costly, and undesirable. Furthermore, recycling wastewater into usable water, environmentally safe water, or drinkable water can be costly, inefficient, and difficult.
Water recovery from wastewater may be important in terrestrial and space applications. Terrestrial applications where water recovery may be important may include water recycling in arid regions, water treatment for disaster relief, greywater recycling onboard ships, wastewater recycling from hydraulic fracturing, wastewater recycling from agricultural, animal, and food production operations, and water recycling at long-term military outposts, ships, and submarines. Space applications where water recovery may be important may include water reclamation to generate usable or potable water in long-term space missions. For example, wastewater in long-term space missions can consist of hygiene water, laundry water, humidity condensate, brines, and human waste (e.g., urine). Due to the high cost of delivering supplies to space, recovery of usable or potable water from wastewater may be critical to life support of crew members. Long duration space missions to the moon, Mars, and near-Earth asteroids may be mass-constrained and may require robust and reliable life support hardware. Closing the water loop on long duration space missions can be crucial to reducing mission mass, cost, and logistics support for orbiting facilities and planetary spacecraft.